


thunder in our hearts

by homeschoolvaledictorian



Series: running up that hill [1]
Category: Assassination Classroom
Genre: Alternate Universe - Canon Divergence, Fluff and Angst, Gen, M/M, child fic
Language: English
Status: Completed
Published: 2016-07-18
Updated: 2016-07-18
Packaged: 2018-07-24 19:16:01
Rating: General Audiences
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 4,109
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/7519972
Author URL: https://archiveofourown.org/users/homeschoolvaledictorian/pseuds/homeschoolvaledictorian
Summary: <blockquote class="userstuff">
              <p>Karma’s parents are out the door. In place of their usual absence is a quiet, bedraggled stranger who looks like she’s spent a considerable amount of time living from couch to couch. Karma narrows his eyes. She’s not getting paid for this. This is clearly a family obligation, rather than a choice. Karma doesn’t know anything about his so-called aunt, but he can’t fathom what would pull someone halfway across the earth to babysit a kid they’ve never met.</p><p>(or, wild speculation into Akabane Karma's childhood, complete with original characters and an AU childhood friendship with Asano Gakushuu)</p>
            </blockquote>





	thunder in our hearts

**Author's Note:**

  * For [tanktrilby](https://archiveofourown.org/users/tanktrilby/gifts).



> Disclaimer: I own neither Assassination Classroom nor any of its characters.
> 
> I started thinking about what little we know of Karma's homelife and his abandonment issues, and decided to torture myself with headcanons. The childhood friendship AU was an idea kindly donated from tanktrilby, who has hopefully slogged through the last of finals. This is for you! Please enjoy this 4,000 word garbage!

There is a stranger in the living room.

Karma studies the woman with rapt eyes, hands knotted behind his back. She’s got red hair like him and his mother, a familiar cast to her facial features, but that’s where the similarities end. The woman’s hair is raggedly cut to her shoulders and tipped with purple, not at all like his mother’s carefully arranged curls. She’s wearing a red beanie and a battered green parka over jeans with holes in the knees, carrying a messenger bag covered in colorful buttons. Her face is youthful, spattered with freckles. She’s got so many little earrings; silver studs and bronze chains and the flash of something bright hanging off her right ear. Karma squints to identity it.

The woman looks at him, an unreadable expression pasted across her pretty face. Karma blinks. Guests of his parents, usually business partners, are always neat and well-dressed. Half of them don’t notice him. The other half offer him vacant smiles, look somewhere over his shoulder, and ask his parents about their son. Karma’s mother laughs and says, “Introduce yourself, sweetheart,” and he does. There are a handful of coos from the more motherly guests over his “I’m Karma, I’m eight and a half years old,” which is apparently the epitome of maturity and intelligence for a boy his age. Karma likes it better when they ignore him.

This woman is different from every other grown-up who’s ever visited. She doesn’t ignore him, but she hasn’t said anything yet, much less anything that reeks of falsehood. Her eyes are blank but powerful, pinning his feet to the floor.

His father clears his throat. There’s a suitcase in his hand and another in the hall. His mother is murmuring into her cell phone, her back to Karma. “Karma, we’re leaving. You’re going to behave, right?” his father asks in a way that implies an answer is neither wanted nor needed. Karma nods anyway. “We’re going to be gone for a whole week. That’s why your aunt is here. She just got back from New York City.”

“You can call me Mirai,” the woman—his aunt—says. “I’m not much older than you, anyway. It’s good to meet you, Karma.”

Karma doesn’t say anything. His eyes flick over to his father, but his father doesn’t see. He’s glancing at his cell phone. “We’re late. Are you ready, Kasumi?”

Karma’s mother slides her phone into her purse and sighs. She grabs her briefcase off the coffee table. “Come here, darling.”

Karma goes to her obediently and she pulls him into a brief hug. “We’ll be back before you know it. Remember, be good for Mirai, and I’ll get you that book you wanted. Okay?”

“Okay.”

“Great.” She kisses him on the forehead, and just like that, Karma’s parents are out the door. In place of their usual absence is a quiet, bedraggled stranger who looks like she’s spent a considerable amount of time living from couch to couch. Karma stares. This time, Mirai blinks, and smiles a little.

Her smile is not especially wide or bright, but it’s inlaid with something inherently kind. Karma narrows his eyes. She’s not getting paid for this. This is clearly a family obligation, rather than a choice. Karma doesn’t know anything about his so-called aunt, but he can’t fathom what would pull someone halfway across the earth to babysit a kid they’ve never met. This has happened two or three times before, and Karma always stays with his father’s parents in Fukuoka.

“I’ve never seen someone with purple hair,” he says, crossing his arms. “Why do you have purple hair?”

Mirai smiles the same tiny smile and shrugs. “I like the color purple.”

“Why did you leave New York City? I’d give anything to go to New York City.”

“I was only there for a job. I live in Tokyo when I’m not working.” Mirai lifts the canvas flap of her messenger bag. Karma peers inside to see a black case. “That’s one of my cameras.”

Karma reaches out a hand before remembering his father’s words, _behave yourself._ People get mad when he touches their things without permission, which is why it’s generally a better policy to wait until he can touch their things without them ever finding out. Mirai angles the bag a little closer. “Go on, take a look, I don’t mind.”

Karma pulls out the camera case. His fingers skim over the glossy surface reverently before popping the clasp. Inside, the camera lies snug in a niche of black satin. An attachable strap and an array of carefully packaged lenses are tucked in an inside flap. Karma has never seen a camera this nice before. He can just imagine all the amazing places it has seen. He shuts the case and pops the clasp back into place.

O-O-O-O-O-O

Without asking or even explicitly telling him, Mirai decides to explore the house. It’s like she can’t settle on any one direction; her hands flutter and her eyes wander from room to room, her feet only a step behind. Karma follows her, half bemused and half nervous, though he can’t say why.

“I haven’t been here before,” she says, absentmindedly running a hand over the leaves of a fake potted lily. “I only met you once, when you were a baby. That was back when your parents still lived in Tokyo.”

He jerks to a stop. They moved here when Karma was three years old. His parents had never been too close to any outside family, but Karma had at least known his grandparents, other aunts, uncles, and cousins. As far as he can remember, Mirai has never been mentioned. Still, his parents had called her and asked her to watch their son for a week while they were away on business. She couldn’t be a complete stranger. But an aunt that Karma can’t remember ever meeting in seven years of holidays and family reunions is odd. Karma is pulled back to the same thoughts: _Who drops everything to babysit a kid they don’t even know? Who does that? What’s in it for her?_

Karma shows her from room to room, most of them empty and unused. This includes two guest bedrooms with adjoining bathrooms, another living room, a study for his father’s work, and a kitchen big enough to feed everyone seated in the dining room. Mirai trails a hand across every photograph hanging on the walls. They feature Karma’s parents’ travels and Karma’s early school years. Karma and his parents are hardly ever in the same pictures. If not for the genetic similarities, a stranger could assume they lead two entirely different lives, and they wouldn’t be far off the mark.

“This is my room,” Karma says, pushing open the door to reveal the messiest, most lived-in space of the house. Clothes are spilling out of the hamper and creeping across the floor towards the closet. A mobile of the nine planets, clearly handmade by its excessive application of glitter, dangles above the star-patterned bedspread. The ceiling is a mess of glow-in-the-dark comets and stars. A world map is tacked next to the desk piled high with books and video games, marked with slips of paper and green thumb tacks.

“My parents,” Karma rushes to explain, jabbing a finger in the direction of the map. “It’s where they go. I ask my mom what day they get there and what day they leave, and then I write it down and pin it on the map. They’ve been to nineteen cities since I started,” he adds proudly.

Mirai lowers her head and gives an enigmatic smile. She inspects the map. “You’re quite the explorer.”

Karma wants to shout his delight, because that’s exactly what he wants to be called. He settles for a voice barely containing his excitement. “You think?” His face crumples, sour. “Well, I’m not. Not yet.”

“You’ve got time.” She waves a hand at the mobile. “Even space?”

“Especially space, because then I could see the whole world. It would be so small I could hold it in my hands and see everything behind it.” Karma kicks the clothes on the floor into a slightly higher pile. “There’s no place I don’t want to go.” He wrinkles his nose. “Even if I haven’t been outside of the country yet.”

“You’ve never been outside of Japan?”

“Well, my mom says I have, when I was a lot younger. But I don’t remember it, so it doesn’t count.”

“I see.”

Karma pulls the blinds shut and clicks the lights off. Above them, the comets and the stars glow a dull green.

O-O-O-O-O-O

After returning to the living room, Mirai pulls out a dog-eared set of cards, the kind he’s seen in the movies in American casinos. His parents brought a set back from Las Vegas a few years ago. It’s been sitting on a shelf dusty and unused ever since. Mirai doesn’t say anything, but Karma knows what she’s going to do as she hands him the set. He hands the cards back, freshly shuffled, and she spreads the set in her hands and tells him to pick a card. It’s the queen of clubs.

Karma puts the card back. Mirai shuffles the deck quickly and efficiently, her wrists twisting and turning in elegant maneuvers. Karma squints, trying to see the trick, but before he knows it, Mirai is holding the set facedown. “Your card’s on top.”

His card is on top. “How did you do that?” Karma asks, fascinated. She demonstrates it again, slower, so Karma can catch the intentional misdirection of her hands as the chosen card slips into its designated spot. It’s hidden behind a flip of her wrist.

“Show me again,” he says. She shows him three more times, until Karma can produce a clumsy replica of her movements. Two hours pass like this in near-silence. Five new card tricks under his belt, Karma flicks the set from hand to hand. “Do you know any more?”

“Unfortunately, I don’t,” Mirai says. “But I have a set of hanafuda cards that we can use to play Koi-Koi. Do you know how to play?” Karma shakes his head. “If you help me with dinner, I’ll teach you.”

Dinner is a sorry affair. Mirai doesn’t know how to cook anything, or anything Karma’s used to, anyway. She shuffles from cabinet to cabinet, becoming increasingly desperate in a search for ingredients and muttering to herself. Karma looks after her, overcome by bewildered amusement. He wonders if he should tell her that he can cook; not much, yet, but a few serviceable dishes. He pulls two packages of instant noodles from the cupboard instead.

Mirai turns around and winces at the sight. “I guess a trip to the supermarket is in order.”

After dinner, they play Koi-Koi. Karma places a blue ribbon card in the middle of the table and watches the flash of his aunt’s right ear. “What’s that?” he asked, pointing.

Mirai absent-mindedly reaches up to feel her ear. “It’s a camera charm. I’m a photographer.”

“Photographer? What do you take pictures of?”

“Whatever people want me to take pictures of,” she says. “Though how I take the pictures is generally up to me. That’s what makes it fun.”

“Where have you been?” Karma asks eagerly.

Mirai thinks for a moment. “There’s not many places I haven’t been to. Africa, western Asia, the Americas. I live in Tokyo, but I love traveling. Rio de Janeiro, San Francisco, Bogotá, Shanghai, Delhi, Nairobi, Boston. Can’t really stay still.”

Karma leans forward before considering that maybe he should at least pretend not to hang off of every word. But Mirai’s seen his room. It’s pointless to hide his excitement, and there isn’t any obvious harm in it.

“Tell me about it all,” he says, voice half-begging.

O-O-O-O-O-O

Mirai is reserved, but she’s less reserved when she’s regaling him with stories from her travels. Karma pauses every minute or two to scrawl a few sentences into a battered spiral notebook. It’s his and Gakushuu’s notebook, and it’s filled with every exotic thing they’ve ever seen and every exotic thing they want to see. Normally, it has a home on Shuu’s desk, but Shuu’s on vacation with his parents and Karma had wanted the notebook. He had told Shuu it was because he was going to explore Ōhori Park with his grandparents, which hadn’t been a lie at the time, since he hadn’t known about Mirai. But that was only part of the reason.

“You do know I’m going to Germany, right,” Shuu had said, half-annoyed and half-confused. “Doesn’t it make more sense for me to have the notebook?”

“You can write all the stuff you learn on fancy German paper,” Karma had replied, sticking out his tongue.

Shuu had rolled his eyes. “Okay, well, bring me back some leaves for my collection, okay?”

“I’ll bring you back a whole sakura tree if it’ll make you happy,” Karma had said cheerfully. Shuu had smacked him on the head with the notebook, but Karma knew he had won when Shuu had handed it over with no further complaint.

Karma misses Shuu.

He takes care in every word Mirai says, faithfully rendering each memory into the notebook to pour over with Shuu another day. He doesn’t notice he’s tired until he falls asleep at the table.

O-O-O-O-O-O

The week passes slowly, but the usual boredom doesn’t come. On Tuesday, they go to the supermarket. Karma pushes the cart with great enthusiasm, careening through the aisles while Mirai buries her face in the grocery list. They play Koi-Koi again, with Mirai gently offering suggestions when Karma doesn’t know what card to put down. On Wednesday, they turn the entire house into a blanket-and-pillow fort and watch movies until midnight. On Thursday, when the heat isn’t so devastating, they go to the local park and Mirai takes pictures of the plants. She even lets Karma take a couple pictures. Afterwards, they buy onsen tomago from a street vendor and sit on a bench by the lake, the water rippling at their feet. Other times, they sit in silence, Karma reading or playing video games while Mirai plays Sudoku or types on her laptop. The presence of someone else is comforting enough.

Karma is happy where he is, which is not a feeling he’s used to without his parents or Shuu around. He unravels around Mirai, and she unravels around him. She’s still quiet, but it’s a comfortable quiet. She laughs and smiles easily, shares herself generously. Karma likes to think, a little selfishly, that he is the one who inspires her generosity, but something tells him that Mirai is always like this: quiet and calm, but wildly intelligent and perpetually in awe of the world around her. Karma is more often in awe of _her._

O-O-O-O-O-O

For example: the piano has been sitting in the attic for as long as Karma can remember. Karma’s never messed with it; his parents told him it was an antique and not to be touched. He’s considered disobeying—how would they really know if he did anything with it?—but he doesn’t know how to play and has never felt any interest in learning. Mirai finds the piano on Saturday and her eyes light up.

“Oh!” She whistles appreciatively, circling the neglected instrument. “Do you play? I know your parents don’t.”

“No,” Karma says. “It’s more for decoration, I think.” He makes a face. “My parents sure are preoccupied with making everything look nice.”

Mirai doesn’t look surprised. “That’s a shame. If you know what you’re doing—” She pulls out the bench and blows on the keyboard, sending puffs of dust towards the ceiling. She places her hands on the keys, gentle as petals falling, and _plays._

O-O-O-O-O-O

Summer break trickles down. On the sticky July afternoon Karma’s parents are supposed to return, Karma’s mother calls. Mirai accepts the call and puts the phone on speaker, holding a finger up to her lips as she continues peeling potatoes. The two of them are at the kitchen table, surrounded by mounds of vegetables. A pot of water is simmering on the stove. Karma grins and lifts the knife onto the cutting board to chop celery. Mirai steals a slice and smiles at him, devouring it in three crisp bites. Karma sticks out his tongue at her, but steals a slice for himself. “Kasumi.”

They talk for a while about the mundane. Mirai talks about Koi-Koi and the blanket-and-pillow fort, but not about her photography or the piano. Half of the conversation feels like an inside joke between Karma and Mirai, which he doesn’t mind in the least. Karma’s mother talks about work in the vaguest terms possible and how lovely the weather in Rome is. Karma listens interestedly while swinging his feet. It becomes clear that Karma’s mother has something to say that she doesn’t want to say.

“I’m so sorry to do this to you, Mirai,” Karma’s mother finally gushes. “But we won’t be home today. Could you stay any longer?”

“Oh,” Mirai says. “Well, I have a shoot in two days. In Tianjin.”

Karma’s mother makes a distraught sound. “I don’t think we’ll be back by then.”

Karma schools his face. He’s never stayed by himself for that long before. But it shouldn’t be very different than a day alone, should it? Maybe they’ll send him a babysitter. Karma doesn’t want a babysitter.

But Mirai’s week is up. She has no more obligation here. She’ll be flying across the world, to Tianjin, to Paris, to Mumbai and Los Angeles and Mexico City. Karma will be stuck here for the foreseeable future, and who would want to be here when they can be everywhere else?

Mirai looks at him then.

“You know,” she says, slowly. “It won’t be a problem. I’ll just reschedule. I can stay for another few days, I bet.”

Karma looks at her again, sharply. Karma’s mother says something else that he doesn’t hear. Mirai’s eyes are tight, but her smile is genuine. “It hasn’t exactly been a hardship. Karma’s been really good. In fact, where can we go to buy that book you promised him? My treat.”

Something warm is trapped in his chest. Karma hides his smile behind his arm and turns back to the pot on the stove.

O-O-O-O-O-O

The next Monday sees them in the science section of Karma’s favorite bookstore. Mirai has shed her usual green parka in the summer heat to reveal a t-shirt for some Swedish band Karma has never heard of. She’s already absorbed in reading the titles of the books on the shelves. Karma rubs a finger down the spine of a medical journal. “I wanna learn about black holes. Mirai, what do you think would happen if you pushed someone into a black hole?”

A woman down the row throws them a startled glance and walks away quickly.

Mirai laughs a little. “Well, I’ve heard that if you were to approach a black hole feet first, then the difference in gravity between your head and your feet would stretch you until you split in half at the waist. Not a very pleasant way to go.”

Karma shifts from foot to foot. “My friend Shuu went to the planetarium with his dad last month. He learned all about stars and comets and stuff. There’s a book on astronomy here. I wanted to read it with him.”

“Your friend Shuu? Why haven’t I met this delightful-sounding young man?”

“He’s away on vacation right now,” Karma says, a little disappointedly. “He won’t be back for another two weeks.”

“What about your other friends?”

“I don’t have any others. I don’t need any more friends. Shuu’s my best friend.” Karma leans down to the bottom shelf where he last saw the book. With a small noise of excitement, he slips it off the shelf. “It’s this one!”

Mirai doesn’t miss a beat. “Well, let’s go pay for it.”

O-O-O-O-O-O

And then it’s over. Before Karma knows it, ten days are up and his parents are standing in the doorway. He runs to see them—a pat on the head from his father, a hug from his mother—and they look wonderfully tired. Mirai has long since packed her messenger bag, so there’s only one thing left to do.

“The taxi outside will take you to the train station,” Karma’s mother assures Mirai as she greets her with a hug. “It’s already been paid for.”

“Thank you.” Mirai turns to Karma. She looks distant, like she’s searching for her words very carefully. Before she can say anything, Karma’s mother interrupts. “What do you say, Karma?”

“Thank you,” Karma says automatically. He scrunches his face in frustration, because that wasn’t enough. “Thank you!”

He stumbles forward. Mirai, as always, opens her arms, and Karma falls into them.

“Please come again,” he whispers. She stiffens, but before Karma can worry about it, she relaxes.

“Of course,” she says.

O-O-O-O-O-O

Though Mirai is frequently traveling and rarely has the time to visit, a steady influx of souvenirs sent to the Akabane residence over the next four years reveals an affection burgeoning between aunt and nephew.

The bookmarks come in a variety of shapes, sizes, and textures, each from a faraway corner of the world. Sometimes Karma just likes to run his fingers over each one, savoring the touch of a thousand different cultures: peach-colored silk from China, coarsely woven reeds from Mexico, jade polished glossy from Myanmar. The bookmarks always arrive with a note documenting Mirai’s latest adventures and recommending a book, signed with love. Karma tracks down the book and attempts to read it, which is not generally an easy task; Mirai likes to recommend books in Japanese and English, but also from a seemingly endless list of other languages like Bengali and Spanish. By the time Karma turns eleven, there are at least eight different foreign language dictionaries scattered around his room. Mirai also likes to recommend books that are difficult to find, often launching Karma across the city to every bookstore and library he knows and a few he doesn’t. After he finishes reading, he carefully pens a detailed analysis of each book, often filled with acerbic insults to the characters’ decisions and overall intelligence, gaping plot holes, and pretentious diction. But Karma, at the end of each letter, always finds something to like about each book.

In the thrill of the chase, dancing through the dusty archives of private collections and the sun-drenched windows of thrift shops, Karma can almost feel Mirai at his back, hand on his shoulder. It doesn’t make him miss her any less.

Other trinkets come packed next to the bookmarks and the notes, wrapped in perfumed paper. A seashell, a string of beads, a fan, anything else that catches Mirai’s fancy as she wanders from market stall to market stall.

“This one felt like you,” she writes with each one.

On his tenth birthday, she shows up on the doorstep, pressing a little wooden peacock carving into his hand. Karma looks at her wide-eyed, squeezes the peacock in his hand, and tugs her into a bone-crushing hug. Mirai laughs and invites herself in for tea, as if she had to be invited.

O-O-O-O-O-O

It’s been four months since the fight with Gakushuu. Neither he nor Shuu has shown any inclination of extending an olive branch, but it takes Karma everything he has not to bang on the Asano’s front door and beg for Shuu to come back, in any capacity possible. Karma would take Shuu’s insults and cutting looks if it meant Shuu would pay him any sort of attention. But Karma refuses to give up any ground on that particular battle, so he follows Shuu’s lead and privately hopes that Shuu feels the same way.

Shuu will be killed by his father’s newly twisted policies of fatherhood. Karma will be killed by his own crippling loneliness. In order to survive, they must adapt.

Their first year of middle school is approaching fast. Karma turned twelve several months ago. So did Gakushuu. They will be in separate classes: Class A for Shuu, Class D for Karma.

His parents are at work. He can’t go over to Shuu’s. There is nothing to do, nothing to explore. Karma would read his and Gakushuu’s notebooks, if he hadn’t trashed them in anger and frustration. Karma would apologize to Shuu in a heartbeat, if he didn’t think it would be an ultimately futile effort. Karma sits by the door, caught in a slow-moving miasma of desolate thought, and stares hopelessly at the mailbox.


End file.
